Chrome console clear assignment and variables

A simple solution to this problem is to wrap any code that you don't want in the global scope in an immediately-invoked function expression (IIFE). All the variables assigned in the function's scope are deallocated when the function ends:

(function() {

    // Put your code here...

})();

For more info on IIFEs: https://en.wikipedia.org/wiki/Immediately-invoked_function_expression

[Update]

In ES6 you can use blocks (so long as you use let instead of var):

{

    // Put your code here...

}

For more info on blocks: http://exploringjs.com/es6/ch_core-features.html#sec_from-iifes-to-blocks

Easiest way to clear data from the console is to refresh the page.

What you are affecting when declaring any variables or functions within the developer console is the global execution context, which for web browsers is window.

When you clear() the console you are telling Chrome to remove all visible history of these operations, not clear the objects that you have attached to window.